The invention relates to a refractory repair material batch for repairing worn areas in refractory linings, in particular in metallurgical furnaces or vessels, e.g. in converters.
Repair materials of this type are also known as hot-repair materials, since they are introduced into the hot furnace or into the hot vessel. They are used to repair what are known as pre-worn locations, i.e. locations in the refractory lining which are experiencing spalling or flaking which does not yet require complete removal and replacement of the refractory lining. In such applications, depending on the nature and structure of the batch, materials are, for example, pneumatically sprayed or cast or poured or introduced by centrifuging. Spraying allows accurate and controlled application to the locations which are to be repaired, and consequently this is the preferred method.
It is known to spray basic hot-repair materials, in particular including basic linings, which are made up with water and generally do not contain any carbon. Moreover, basic hot-repair materials which may contain carbon and are anhydrous are also known. However, these repair materials cannot be sprayed.
The water in the hot-repair materials leads to very substantial thermal shocks at the repair locations and therefore to the formation of cracks which adversely affect the success of the repair. Moreover, it is only possible to achieve relatively low bonding forces between repair material and repair location, and consequently the wear resistance at the repair location is reduced. Moreover, the water attacks the basic material of the refractory lining, which may be destroyed by hydration.
Although carbon-containing hot-repair materials do not have the abovementioned drawbacks of the water-containing hot-repair materials, they cannot be sprayed.